'I have had the best and the worst day of my life in 2015': Catherine Britt celebrates six Golden Guitar nominations seven months after she was diagnosed with breast cancer

She was diagnosed with breast cancer earlier this year, but Catherine Britt is in incredibly high spirits given her challenging year.

The Australian country music singer has been nominated for six Golden Guitars, including Album Of The Year for her sixth studio album, Boneshaker.

The 30-year-old musician took to Instagram on Tuesday to share a snap of her grinning broadly, with her fingers reflecting the number six, reflecting on the 'year of extremes' she's had.

'I have had the best day of my life and the worst day of my life in 2015,' she wrote.

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'I have had the best and the worst day of my life in 2015': Country singer Catherine Britt celebrated her six Golden Guitar nominations with a message of reflection on Tuesday

'The low of my diagnosis and the ongoing treatment but the highs of my wedding day, my ARIA nomination, a successful 6th album and solo tour among other things and now this.... I'm speechless, grateful and so darn happy right now.'

Daily Mail Australia reached out to Catherine's management on Wednesday, but was informed the singer had been in for chemotherapy that morning.